The Voice: Which Coach's Career Was Boosted The Most By The Show?

Out of Christina Aguilera, Cee Lo Green, Adam Levine and Blake Shelton, which of their careers was boosted the most by appearing as a coach on NBC’s “The Voice”? Plus, which of the other coaches would Christina most likely allow to babysit her son, Max? “The Voice” airs Mondays and Tuesdays at 8/7c on NBC.